É a primeira vez que trabalho com os serviços de localização e estou atingindo este erro de vinculador:

Símbolos indefinidos para a arquitetura i386: "_OBJC_CLASS _ $ _ CLLocationManager"

Eu adicionei#import <CoreLocation/CoreLocation.h> e adicionou as seguintes linhas noviewDidLoad

 CLLocationManager *manager = [[CLLocationManager alloc] init];
manager.delegate = self;
[manager startUpdatingLocation];
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

if (![CLLocationManager locationServicesEnabled]){
    UIAlertView *servicesDisabledAlert = [[UIAlertView alloc] initWithTitle:@"Location Services Disabled" message:@"You currently have all location services for this device disabled. If you proceed, you will be asked to confirm whether location services should be reenabled." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [servicesDisabledAlert show];
    [servicesDisabledAlert release];
}
[manager release];